Sir Edward Coke, Third Institute 61641
It was further provided by the said Act of 33 H. 8. that if a man attainted of treason became mad, that notwithstanding he should be executed; which cruell and inhumane law lived not long, but was repealed, for in that point also it was against the common law, because by intendment of law the execution of the offender is for example, ut poena ad paucos, metus ad omnes perveniat, as before is said: but so it is not when a mad man is executed, but should be a miserable spectacle, both against law, and of extreame inhumanity and cruelty, and can be no example to others.
The Founders' Constitution
Volume 5, Amendment V, Document 5
The University of Chicago Press
Easy to print version.